This application relates to a refrigerant system having a common evaporator, but separate condensers where at least one of the condensers is connected to an intermediate pressure compression stage, while the other condenser is connected to a high pressure compression stage, and wherein a reheat coil is incorporated into the refrigerant cycle.
Refrigerant systems are utilized in applications to change the temperature and humidity or otherwise condition the environment. In a standard refrigerant system, a compressor delivers a compressed refrigerant to a heat exchanger, known as a condenser, which is typically located outside. From the condenser, the refrigerant passes through an expansion device, and then to an indoor heat exchanger, known as an evaporator. At the evaporator, moisture may be removed from the air, and the temperature of air blown over the evaporator coil is lowered. From the evaporator, the refrigerant returns to the compressor. Of course, basic refrigerant cycles are utilized in combination with many configuration variations and optional features. However, the above provides a brief understanding of the fundamental concept.
Refrigerant cycles are known, wherein a so-called economizer circuit is incorporated. In an economizer circuit, a first refrigerant line is tapped from a main refrigerant line downstream of the condenser. The tapped refrigerant line is passed through an expansion device, and then the tapped refrigerant and the main refrigerant both flow through an economizer heat exchanger. The tapped refrigerant subcools the main refrigerant, such that when the main refrigerant reaches an evaporator, it will have a greater cooling potential. The tapped refrigerant, having subcooled the main refrigerant, is returned to the compressor at an intermediate compression point.
In some cases, while the system is operating in a cooling mode, the temperature level at which the air is delivered to provide a comfort environment in a conditioned space may need to be higher than the temperature that would provide the ideal humidity level. Generally, lower the temperature of the air stream more moisture can be removed from this air stream. However, lowering the air temperature below certain level is undesirable. This has presented challenges to refrigerant system designers. One way to address such challenges is to utilize various schematics incorporating reheat coils that will increase the air temperature. In many cases, a reheat coil placed in the way of an indoor air stream behind the evaporator is employed for the purposes of reheating the air supplied to the conditioned space after it has been cooled in the evaporator, and where the moisture has been removed.
While reheat coils have been incorporated into air conditioning systems, they have not been utilized in an air conditioning system having an ability to reject heat at multiple temperature levels.
The present invention employs the flow of refrigerant from an intermediate compression point in a compressor to selectively provide refrigerant to at least one of a plurality of condensers, where each of the condensers operate at different temperature levels. In this manner, the heat rejection characteristics of the refrigerant cycle can be controlled to provide enhanced flexibility to a refrigerant cycle designer. Also, improved dehumidification function is provided by incorporating a reheat coil into the refrigerant system.